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Snakes, spiders and heights are all it takes to send many of us cowering in the corner. Public speaking might as well be called public sweating.

Some fears are just universal, but they don’t have to be misunderstood. Most are evolutionary, experts say, and develop as a response to situations thought to cause harm, such as a poisonous bite, or, in the case of a closed space, those that make us vulnerable to a predator. And if they aren't innate, we can easily pick them up from our parents or by watching a frightening experience, such as a near-drowning.

“They all have some potential threat of danger,” says Jerilyn Ross, president and CEO of the national nonprofit organization the Anxiety Disorders Association of America. “The higher the person's perceived threat of danger, the more frightened the person will be.”

Fortunately, for the majority of the population, these responses are normal and oftentimes useful.

Children, for instance, may retreat from a high ledge because they sense they could get hurt. Fear of public speaking, which can bring even the toughest prosecutor to his knees, stems from the concern that he’ll be judged and seen as inadequate, unattractive and dumb. As a result, he may spend more time preparing to make sure his presentation goes smoothly.

But others, who experience irrational or excessive reactions to feared objects or situations known as phobias, deal with an entirely different brand of dread.

Anxiety disorders on the riseRoss herself once had a phobia of heights, which for years wouldn’t allow her to go above the 10th floor of her workplace, despite the fact that she was an avid skier. Phobias, she says, can come out of the blue. A person may have a panic attack while driving across a bridge, suddenly feeling an overwhelming sense of impending doom, rapid heart beats, the sweats, trembling and chest pain. The fear of another attack can make him or her go to great lengths to steer clear of bridges, or whatever circumstance triggered the reaction in the first place.

According to the Anxiety Disorders Association of America, 19 million people have specific phobias, such as crossing bridges or tunnels; 15 million have a social phobia, e.g., public speaking; and 2 million have agoraphobia, when sufferers avoid places where they previously had a panic attack. Those who have one phobia likely have others too.

The bad news is that more of us are experiencing these kinds of anxiety disorders, says Robert Leahy, president of the International Association for Cognitive Psychotherapy and director of the American Institute for Cognitive Therapy. In his upcoming book tentatively titled Anxiety Free, Leahy discusses how we came to live in the “age of anxiety.” The average child today, he says, has the same level of anxiety as the average psychiatric patient in the 1950s.

Much of the rise in anxiety is related to people feeling their connections with others are less stable — there’s been an increase in divorce, fewer people are getting married and they’re less engaged in their churches, synagogues and local institutions such as the PTA. Surveys show that while many Americans’ lives are improving in every material way, their expectations for happiness are also rising and they feel less satisfied. Acts of terrorism, despite the low odds of actually being affected by one, have made walking through airport security and riding the subway in a major city more stressful.

Treatment possibilities existBut don’t get too depressed. According to experts, major anxiety problems are treatable.

For phobias, that primarily means cognitive behavioral therapy. It involves helping people face their fears and overcome them, says Dr. Brian Doyle, clinical professor of psychiatry and of family and community medicine at Georgetown University Medical School. By confronting the feared object or situation in a gradual way, people learn to control their reactions. Because certain situations are difficult to access or recreate, some psychologists are even using virtual reality as an aid.

Doyle, who often works collaboratively with psychologists to treat patients, says there are a few different groups of medications, such as beta-blockers, benzodiazepines and SSRIs that can calm the body or provide short-term relief of anxiety too.

Though not a cure, therapy can help people live normal lives again. But It isn't easy, says Barbara Rothbaum, a professor in psychiatry and director of the Trauma and Anxiety Recovery Program at the Emory University School of Medicine.

“Being scared of something,” she says, “and doing it anyway to get over it — (that) takes courage.”